Malignant gliomas, the most common form of central nervous system (CNS) cancers, are currently considered essentially incurable. Among the various malignant gliomas, anaplastic astrocytomas (Grade III) and glioblastoma multiforme (GBM; Grade IV) have an especially poor prognosis due to their aggressive growth and resistance to currently available therapies. The present standard of care for malignant gliomas consists of surgery, ionizing radiation, and chemotherapy. Despite recent advances in medicine, the past 50 years have not seen any significant improvement in prognosis for malignant gliomas. Wen et al. Malignant gliomas in adults. New England J Med. 359: 492-507, 2008. Stupp et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. New England J Med. 352: 987-996, 2005.
A major reason for the poor prognosis of malignant gliomas is the difficulty in delivering a sufficient quantity of chemotherapeutic agents to the brain. Drug access to the brain is limited by the blood brain barrier (BBB). The concentration of drugs that finally reach the brain is further decreased by hepatic first-pass metabolism and urinary excretion. Therefore, invasive surgeries are often required, such as tumor resection, stereotactic injection of anti-tumor medication, or placement of catheters for convection enhanced delivery of medication.
Intranasal delivery of a drug offers a novel non-invasive therapy to bypass the blood brain barrier and to rapidly deliver pharmaceutical agents to the CNS directly. Intranasally administered drugs reach the parenchymal tissues of the brain, spinal cord and/or cerebrospinal fluid (CSF) within minutes. In addition to delivery via the olfactory tract and trigeminal nerves, it appears from animal studies that the therapeutic drug is also delivered systemically through the nasal vasculature. Hashizume et al. New therapeutic approach for brain tumors: intranasal delivery of telomerase inhibitor GRN163. Neuro-oncology 10: 112-120, 2008. Thorne et al. Delivery of insulin-like growth factor-1 to the rat brain and spinal cord along olfactory and trigeminal pathways following intranasal administration. Neuroscience 127: 481-496, 2004. Intranasal delivery of therapeutic agents may provide a systemic method for treating other types of cancers, such as lung cancer, prostate cancer, breast cancer, hematopoietic cancer and ovarian cancer, etc.
Perillyl alcohol (POH), a naturally occurring monoterpene, has been suggested to be an effective agent against a variety of cancers, including CNS cancer, breast cancer, pancreatic cancer, lung cancer, melanomas and colon cancer. Gould, M. Cancer chemoprevention and therapy by monoterpenes. Environ Health Perspect. 1997 June; 105 (Suppl 4): 977-979. Oral perillyl alcohol has been used in a recent phase I trial sponsored by the National Cancer Institute. Although oral perillyl alcohol did not induce severe adverse effects, it was generally poorly tolerated, mainly due to gastrointestinal side effects. In addition, its anti-cancer efficacy was limited. As a result, the use of oral perillyl alcohol was discontinued. Ripple et al. Phase I clinical and pharmacokinetic study of perillyl alcohol administered four times a day. Clinical Cancer Res 6: 390-6, 2000.
In order to minimize the gastrointestinal side effects of oral POH and to provide a means of delivering POH directly to the central nervous system, a nasal formulation of POH (see below) for direct intranasal delivery of POH to malignant brain tumors was studied by Dr. Clovis Fonseca at the Fluminese University in Brazil. Da Fonseca, et al. Anaplastic oligodendroglioma responding favorably to intranasal delivery of perillyl alcohol: a case report and literature review, Surgical Neurology (2006) 66:611-615. This formulation of commercial grade POH combined with a solvent cocktail, has already been delivered to 150 patients with recurrent malignant gliomas, with minimal side effect and a six month 50% progression free survival rate. Da Fonseca et al. Correlation of tumor topography and peritumoral edema of recurrent malignant gliomas with therapeutic response to intranasal administration of perillyl alcohol. Invest New Drugs 2009, Jan. 13.
Commercial grade perillyl alcohol, with purities ranging from 85% to 96%, is typically purified from natural products, or by synthetically modifying natural products such as beta-pinene (extracted from pine trees). Inevitably, perillyl alcohol obtained through these routes is contaminated by its isomers and other impurities which have similar physicochemical properties, and, therefore, are extremely difficult to remove from perillyl alcohol by conventional purification methods such as fractional distillation or chromatography. Isomers of perillyl alcohol and other impurities may be potentially inhibitory towards the desired therapeutic properties of perillyl alcohol.
Consequently, there is still a need to prepare highly purified perillyl alcohol and use this material in the treatment of CNS cancers such as malignant gliomas, as well as other aggressive brain tumors. Purified perilly alcohol may be administered alone or in combination with other treatment methods including radiation, standard chemotherapy, and surgery. The administration can also be through various routes including intranasal, oral, oral-tracheal for pulmonary delivery, and transdermal.